Telephone-circuit.



, UNIT-ED n STATES PATENT OFFICE.

WILLIAM EDWIN PEMBLETON, OF WITTENBERG, WISCONSIN.

TELEPHONE-CIRCUIT. r

SPECIFICATION forming part Of Letters Patent No. 678,304, dated. July 9, 1901.

I Application filed June 27, 1900. Serial No. 21,770. (No model.)

To all whom, it may concern.-

Be it known that I, WILLIAM EDWIN PEM- BLETON, a citizen of the United States, and a resident of Wittenberg, in the county of Shawano and State of Wisconsin, have invented a new and Improved Telephone-Circuit, of which the following is a full, clear, and exact description.

This invention relates to improvements in to telephone-circuits; and the object is. to so arrange the circuit as toenable subscribers to know whether'the operators set at central is cut in or out while conversation between two subscribers is being carried on, and, further,

to make it impossible fora third party to be connected by the operator carelessly or otherwise with the two talking subscribers.

I will describe a telephone-circuit embodying my invention and then point out the novel features in the appended claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate'corresponding parts in both the figures.

Figure 1 is a diagrammatic view of a tele phone-circuit embodying my invention, and Fig. 2 is a partial elevation and partial section of a switch mechanism employed.

Referring to the drawings, 1 designates a 0 switchboard arranged at central, upon which double switches are arranged. I have here shown double spring-switches 2 and 3, the spring-switch 2 beingadapted for engagement with either one ofthe switch-points 4 5, while the spring-switch 3 is adapted for engagement with either one of the switch-points 6 7, and attached to the spring-switches are the jack-plugs 8, 9, 10, and 11.

For illustration I have shown two subscribers lines A and B. The plug 8 may 2o, 21, 22, 2s, 24, 25, 2e, 27, 2s, and 29. These serve to close the line A in the jack 12, and the plug 9 may serve to close the line B in the jack 13. Arranged in the central office are spring switch-points 14, 15, 16, 17, 18, 19,

severalswitch -pointsare arranged in pairs, the several pairs forming a set. Another set comprises spring switch points 30,31, 32,33,-

34, 35, 86, 37, 38,39, 40,41, 42,43, 44, and45.

The end contact-plates of each set are curved in such manner as to form a locking device for a circuit-closer, as will be hereinafter described.

The circnit-closers of the sets consist of swinging levers 46 and 46, each carrying at one end oppositely-extended arms 47 and 48 and 47 and 48, of insulating material, and on these extended arms are metal sleeves 49 and 50 and 49 and 50 designed to close'the circuit through pairs of contact-plates, as will be hereinafter described.

The operators set comprises a transmitter 51 and a receiver 52, and also arranged in the operators set is an extra large transmitter 53, in front of which alarm-sounding devices, such as bells 54 and 55, are placed.

These alarm devices are designed to be sounded one after the other, and they are of difierent pitch, so that by their succession of sound ing a subscriber may know the position of the switch mechanism in the operators set.

In operation, assuming that the subscriber A wishes to call subscriber B, A rings up central, and the operator inserts the plug 8 into the jack 12, the plug 8 being connected with the plate 2, from which a wire 56 extends, and has connections with the spring-contacts 18, 22, and 26. The circui t-closing sleeves 49 and 50 are normally held in engagementwith the contact-springs 14 and 15 and 16 and 17 by the locking connection of said spring-plates. As the lever 46 is moved to force the circuitcloser forward the sleeve 49 closes the circuit through the contact-springs 18 and 19, While the sleeve 50'closes thecircuit' between the contact-springs 20 and 21. As the movement is continued these spring-contacts are released, as they engage but slightly with the circuit-closers, and then the sleeve 49 closes the circuit between the contact-springs 22 and 23 and the sleeve 50 closes the circuitbetween the contact-springs 24- and 25, the connections being made simultaneously. Upon' a still further movement of the lever 46 these last-named connections are broken and connections are made between the contact-springs 26 and 27 by the sleeve 49-and the circuit .is

closed between the contact-springs 28 and 29 by the sleeve 50, and as these last-named'con tacts are made to look into engagement with the circuit-closers the said circuit-closers will beheld in this position until pressure is brought to bear to remove them upon backward movement. Now when the circuit is closed through the contact-springs 18 and 19 they connect the line 56 and the line 57,which passes through the receiver 52, and thence through the secondary 58 of the induction-coil to the ground. As the plug A is at this time connected to the jack 12 by closing contactsprings 18 19, they connect operators secondary circuit with subscriber A at the instant the bell 54 is sounded. At this time the contact-springs 20 and 21 are connected, and they close the circuit through the line 59, bell 54, transmitter 53, and line 60, through the battery 61, and the primary 62, to the bell 54, causing said bell to sound, said sound being conveyed through the transmitter 53, through the secondary circuit 58, the wires 57 and 56, to the subscriber A, through the plug 8 and jack 12. It will be seen then that by closing springs 20 and 21 they cause bell 54 to sound, said sound being conveyed to subscriber A in the manner just described, thus informing A that the operator at central is in the act of connecting his set with As line. When the contact-springs 22 and 23 are connected, it again closes the circuit through the Wires 57 and 56 to the subscriber A, and the contactsprings 24 and 25 being connected closes the circuit through the bell 55, the transmitter 53, the primary 62, line 60, to spring 25 and through the bell 55 and wire 63 to the springcontact 24. This sounds the bell 55, the sound being conveyed through the transmitter 53 to the subscriber A through the wires 57 and 56, &c., as before described. By connecting springs 22 and 23 we can connect operators secondary circuit with As line at the instant that the bell 55 is caused to be sounded by closing springs 24 and 25, the sound being conveyed to subscriber A, informing him that the operators set is now connected with his line.

When the circuit -closer 46 is used, the sleeve 49 must connect the contact-springs 14 and 15 and the sleeve 50 connects the contactsprings 16 and 17. The circuits are then as follows: The object of the connection by springs 14 and 15 through sleeve 49 is to render it impossible for the operator to again cut out signals and still remain connected with the subscribers line. The sleeves 49 and 50, which had connected the contact-springs 3031 and 32 33, respectively, when moved close the secondary circuit 65 through springs 34 35, line 66, springs 17 and 16, line 67, to the wire 57 and thence through the receiver 52 and induction-coil 58 to the earth. The contact-sprin gs 36 and 37 being closed makes the circuit through the wire 67, wire 59, bell 54, transmitter 53, coil 62, and lines and 68,'causing said bell 54 to sound and give the alarm, as before described. Contact-springs 30, 31, 32, and 33 will be used only in case a third circuit-closer is used with another set of connecting-cords, 30 and 31 being similar and for the same purpose as for 14 and 15that is, to prevent the operator from using 46 to connect his set to the subscribers line while using a third contact closer to again properly cut out signals in the same manner as described in connection with the parts 14 and 15. WVhen the contact springs 38 and 39 are closed simultaneously with the closing of the contact-springs 40 and 41, the circuit is closed through the wires and the contact-springs 38 and 39, line 66, and springs 17 and 16, the lines 67 and 57, through the secondary 58, to the earth. At the same time the circuit of the bell 55 is closed through the wires 63 69, the bell 55, transmitter 53, primary 62, wire 60, wire 70, springs 14 and 15, and line 71 to contact 41. Contact-springs 38 and 39 being closed connect operators set with subscribers line at the instant that the bell 55 is sounded by closing springs 40 and 41, thus informing the operator that the operators set is fully connected with the subscribers line. The contact-springs 42 and 43 being connected makes the operators secondary circuit for the circuit closer 46 through wire 65, contact-springs 42 and 43, Wire 66, contact-springs 17 and 16, wire 67, wire 57, through the receiver 52, and thence through the secondary 58 to the ground. The contact-springs 44 and 45 being closed makes the operators primary circuit for the circuitcloset-46 as follows: from the contact-spring 45, through the Wire 64, primary 62, the wire 60, to the contact-spring 44.

The method of ringing is given, although it is not part of the present invention. By pressing the spring-contact 2 into engagement with the contact 4 the operator can then ring through theconnect-ing cord and plug 9 and jack 13, and it will be seen that by pressing the ringing-contacts, as shown, the operator can ring through any coil. It will further be seen that the operator cannot cut in his set without first ringing the bell 54 and then the bell 55. In cutting out the ringing of the bells is reversed, thus indicating to subscribers that the line is free from listening or interruption by the operator. It is manifest that a third party cannot be connected with the two conversing parties by means of the two switches 46 and 46, because when one switch is closed it cuts out the switches to the right of it.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. In a telephone-circuit, a transmitter in the circuit at the central office, and a plurality of alarm-sounding devices of different tone or pitch, and arranged in the circuit adjacent go (tihe said transmitter, substantially as speci- 2. In a telephone-circuit, a transmitter in the circuit at the central office, two bells of difierent pitch arranged adjacent to the transmitter and in the circuit, and a switch operating to close the circuit through the bells one after the other, substantially as specified.

3. In a telephone-circuit, a transmitter in the circuit at the central ofiice, bells of difpitch arranged forward of the alarm-transferent pitch arranged adjacent to the said mitter, and means for successivelyclosing the transmitter, the said bells being arranged in circuit through said' bells, substantially as I 5 different circuits adapted for connection with specified.

5 the main telephone-line, and a switch mech- In testimony whereof I have signed my anism operated in two directions to succesname to this specification in the presence of sively close the bell-circuits during both backtwo subscribing witnesses. ward and forward movements of the switch, T T Substantially as specified I WILLIAM EDWIh PEMBLHTOL.

IO 4- In a telephone-circuit, an alarm-trans- Witnesses:

mitter arranged at central in the circuit, an P. F. DOLAN, operators transmitter, and bells of different WM. G. HEINS. 

